Many practitioners in the chemical and polymer arts are limited by problems associated with achieving thorough and uniform mixtures of liquids, solids, or combinations thereof. The chemical engineering literature, for example, is replete with references as to how to achieve such mixing. It is well known that mixing, especially of high viscosity fluids, is effected by the general processes of shearing and kneading the fluid by the application of shearing forces. Processing fluids of high viscosity requires application of high torque to the mixing element in the fluid. One particular method of achieving the desired mixing is to force the fluid through a narrow gap or plurality of narrow gaps to effect the shearing and kneading.